We need air filters so that we can breathe better air. The air we breathe everyda is full of dust particles and gases that can harm us But what about inside our homes, shopping malls, office buildings or hospitals? Surely a better environment with fresh air is expected. That’s where FILTERs come in.
Air filters are usually made of fine fibers that can trap particulates of different sizes. Inertial impaction, interception, straining and diffusion- are the four terms found in the books which clarifies the physical process of filtration. Basically these are methods how bigger to smaller particles get trapped in the air filter media. That’s how air filters keeps your indoor air quality good and helps you to breathe purified air.
This is a general misconception. Everyone thinks that all the dust is outside. But in reality there are so many sources inside your home or building that contaminates the air. The things we use everyday generates dust. Tobacco smoke, hairs of pets, carpets, room dust, volatile organic compounds (VOCs) like perfumes, exterior dust and soil- all of these can cause you health issues. So indoor air quality should not be taken for granted. That’s why your HVAC must be equipped with the right filters.
HVAC stands for Heating, Ventilation and Air Conditioning. HVAC is the technology of indoor and vehicular environmental comfort. Its goal is to provide thermal comfort and acceptable indoor air quality. Air filters are a unavoidable part of it as it has to control air quality. Your air filter is most likely located right next to your furnace or air conditioning system air handler. The air handler is the large box containing the fan and fan motor. The air handler pulls air in from the house through the return duct system, and then blows the air through the heating or cooling system and back into the house through the duct system.
There are no easy answers..Even HVAC handlers, AHU makers don’t have a clear answer for it. But on the contrary, it’s the most important question also. There are some standards like EN, EU which can help you choosing. The new MERV rating is a standard which also rates filter efficiencies. But before choosing filters you have to know your indoor air quality and source of contaminants in your building campus. How? Just send us a enquiry or give us a call. We are always ready to help you. Keep in mind that a wrong-filtration is just like a no-filtration.
Air filters are nothing but a mechanical component containing a filter media, a frame to hold the media in place and some extra features according to specific need. The main difference in them is in the media which does the real work of filtration. Basically there are 3 types of air filters. Let us get into some depth-
Pre-filter: These are a strong primary stage filter which traps the course particles of the air and keep the finer filter stages safe and long lasting. We make pre-filters which are capable of trapping particulates of size down to 10 microns. They are usually washable. (Filter class of G1 to G4 according to EN standards)
Fine-filters: Secondary filters which are capable of trapping 99% contaminants down to .5 micron size. They are usually made as pockets which have a very good dust loading capacity without much pressure drop.
HEPA filters: Ultimate efficient filters made of micro glass fiber paper. These trap 99.97% of particulates down to 0.3 microns. As a matter of fact, particles having size of 0.3 microns are most difficult to stop. (Do you know diameter of a general hair strand of a human ranges from 20 to 200 microns!!) So A HEPA (High Efficiency Particulate Air) does not allow almost anything to penetrate through it other than fresh air.
So you need to choose a filter or some stages of filters according to the contaminants of your air, keeping in mind the air flow, dust holding capacity and pressure drop.
Because these are the factors that affect the life of your filter. When a filter gets loaded with dust, its efficiency increases but the pressure drop between its upstream and downstream side increases also. After a specific time the filter is no longer able to give you the amount of air flow you require. More the dust holding capacity, the more time your filter will get before it gets clogged. Once it gets clogged you have to change the filter.
Filters do cost you some money. But not as much as your life. If you change the cheap pre-filters on a regular basis, you can get a longer life of the finer ones. A wrong perception in the industry is that people think changing filters is costly. But when you will get a close look on the extra power requirements cost of your Air Handing Unit due to its deterioration by unfiltered air, filter changing will look cost effective to you for sure.
A good filter gives you required efficiency throughout its lifetime. But what’s it good for if its lifetime is too short? So a really good filter should offer you a strong hindrance to the unwanted particles, it provides you the required air flow without a fast pressure drop increase. It should have a good dust holding capacity. Other criteria are also there like water repellency, fire resistance, a minimum rigidity to hold the pleats in position, leak proof and long life. It seems that finding the perfect filter for your purpose is not easy enough. Well, may be. So you need to take a smart decision in choosing the right air filters.